Posting some photos of my progress so far.
I've built the ventilation's silencer boxes using 15mm OSB, lined inside with 50mm insulation.
Four of them, two for each air path (fresh and exhausted), one on each side of the room (in and out).
Added two layers of 12.5mm gypsum board over the 15-20mm OSB/mdf of the boxes and interconnections.
All layers mould proofed, glued, screwed, caulked, primer coated and painted.
Working as calculated (Thanks Gregwor!!!) moving a big mass of air but really slow, no sound leaking neither inside nor outside, no audible sound of the motor, the moving air and finally the speakers.
There is a thing though.
I can see that when I move really close to a power outlet (that would be close to a wall that has a drilled hole for fixing an external power outlet), fresh air is coming inside from the cracks of this hole (all walls are double brick with air gap inbetween).
Like the fresh air coming inside from the ducts is not enough for replacing the exhausted and like trying to get more from all possible openings ( as the door is totally sealed).
Not sure why this is happening, I only calculated the total static pressure for the system. Maybe I had to compare in and out paths to be matched..
Since the system is working on a single motor which exhausts the air, thus forcing the fresh air to get in, I was wondering if adding a second motor to push the air inside would fix this issue?
Boxes and inside work:
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